Caves in the Mountains Are Seldom Unoccupied
by TheMadKatter13
Summary: [COLLAB W/STARRYSUMMERNIGHTS] "This isn't something to play at, Sherlock," he snapped. "If it doesn't work out- what you're asking of me- we can't shrug and say 'oh well, at least we tried'. If we do this… I could seriously hurt you. Do you understand? I could lose control. I could… I could kill you." AU. Top Werebear John / Bottom Human Sherlock.


**First time collaboration with starrysummernights (FFN u/4350426/starrysummernights).**

 **Originally posted to AO3 (AO3 works/5774032) 2016-01-21 (I forgot to cross-post).**

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The cold wind howled outside the mountain cave, sending flurries of snow flying through the air and accumulating on the already heavily covered slopes. Inside the cave that John was hospitable enough to share with Sherlock, it was toasty and warm. A fire crackled in the pit that John had dug himself and there was enough wood stacked nearby to last them through the snowstorm. The firelight made Sherlock's bared body glow where he lay on his back alongside it, pale skin on clear display for the lover attempting to abandon him 'for his safety' for three days.

"Stop being ridiculous, John." Sherlock's voice echoed in the small, barren cave he'd found the ex-soldier in almost a month ago while he'd been trekking through the Afghan mountains on an assignment for Mycroft in a search for drug smugglers. "If you leave me during this storm, I'll freeze to death. It would be more logical for you to remain and keep me warm. Your fur will be excellent in that regard."

"You won't freeze," John replied, avoiding looking at Sherlock as he stoked the fire into a roaring blaze and carefully re-stacked the wood nearby. "There's plenty of wood to last you while I'm gone, and the blankets are still in a pile in the back where I shoved them last. You'll be fine." He gave Sherlock a tight smile and ah- there it was. John's eyes raked down Sherlock's body for a split second before darting away again. Sherlock's confidence grew and he stretched himself languidly, knowing how the light played in the dips and curves of his body, drawing John's eye like the veritable moth to a flame.

John was being ridiculous. Going on and on about how he couldn't 'ensure Sherlock's safety' during his transformation and that he might 'lose control'. That he didn't 'trust himself' to be around Sherlock while he transformed.

Sherlock knew John was fearful of himself, of what he was capable of. He'd been told how John had been bitten one night little more than a year ago, ravaged by a werebear when he'd wandered too far away from his troop's camp. He'd barely recovered from the attack and still bore the scar on his shoulder, visible proof of how close he'd come to death. When the next full moon rose and John had discovered what he was- and how his life had changed- he'd taken himself away from society, hidden himself in this cave in a godforsaken mountain in Afghanistan. He was afraid he would hurt people.

Then again, John was an idiot; he was incapable of harming Sherlock.

"Even if I don't freeze, I'll be lonely without you," Sherlock murmured, eyelids lowered coyly, a tactic he knew John had a weakness for (the whispered praise for the contrast of his dark eyelashes against his pale cheeks had once been the cause of a particularly slow and devastating orgasm). He kept his eyes locked on John's as he rolled onto his side, staring up at him through his eyelashes when he sucked two fingers into his mouth before reaching behind himself and tracing the tight, puckered ring of his hole. "I'll be-" he pressed the tip of his finger in "- _so_ lonely."

John's eyes flashed a luminescent gold and Sherlock's heart skipped a beat as pure adrenaline shot through him. He hadn't seen John transform, had only heard about it from him, brief snatches of conversation in the quiet, languid moments after they'd made love when John's tongue was loose and his thoughts uninhibited. Even then, he called it a 'curse'. But John, while lovely and trustworthy, was an unreliable narrator when it came to himself. He spoke of pain and fear, the urge to hunt and kill, of drinking the blood of his prey and reveling in the _wildness_ of his change. According to John, he kept none of good traits- his restraint, his loyalty, his affectionate attentions- when he turned into the bear. Sherlock had to see for himself.

"I'm leaving," John declared firmly… though he made no move towards the entrance of the cave. He remained frozen in place, watching Sherlock intently with a single-minded, unwavering focus. Like a predator.

"And I'm coming." Sherlock grinned, pressing his finger deeper, wishing he'd thought to grab the oil they'd been using for lubrication. "Or I will be once you get that cock of yours back in me. Insatiable cock slut for you, remember? There's still time before the moon rises. So much time that you can use to open me wide enough for you."

John shuddered, his tongue snaking out to lick his lips, and Sherlock watched as his nostrils flared, scenting the air. No doubt John smelled the lingering scent of the rabbit they'd cooked for dinner, the smoke from the fire and burning wood, and, woven throughout, the musk of Sherlock's arousal. There was another brief flash of gold - there and gone - in John's eyes before he shut them tightly, physically turning away from Sherlock as if that would somehow steel his resolve.

"This isn't something to play at, Sherlock," he snapped. "If it doesn't work out- what you're asking of me- we can't shrug and say 'oh well, at least we tried'. If we do this… I could seriously hurt you. Do you understand? I could lose control. I could… I could kill you."

"You won't," Sherlock said confidently. He trusted John. Utterly and without question.

They had been lovers for a few weeks, since the second night of Sherlock's stay in John's cave, and John had proven time and again how gentle and loving he was. Sherlock _knew_ John would never hurt him. John had been without companionable human contact for so long, isolating himself in the mountain cave as penance for being what he was, that the first time they had had sex, John had been rough and demanding in his raw enthusiasm. Even still, he'd made sure Sherlock had been taken care of, that he wasn't being _too_ rough, that Sherlock was just as aroused and mindless as he was, even as he lost himself in Sherlock's body.

"You can't know that," John growled. It was an animalistic sound, rumbling from deep in the man's chest, more bear than man. John's eyes widened and he slapped a hand over his mouth, taking several quick, panicked steps away from Sherlock, not stopping until his back was pressed against the cave wall. Sherlock remained still and leashed his impulse to scramble after his lover. He knew that if he spooked John now, the man was sure to bolt into the snow and not return until after his transformation was over and he turned human again.

"What I know, John, is that I trust you more than I have ever trusted anyone," Sherlock confessed, wincing as he pushed another finger into his arse, stretching himself as best he could. He'd never tried fingering himself practically dry before, but perhaps putting himself in a little bit of pain would entice the doctor side of John, would make him crave to take care of Sherlock… And once he'd lured John close enough... "Man or bear, you will take care of me unfailingly. You alone make sure I'm fed. Rested. Safe. No one else has ever done that before for me. Ever." He tensed at the friction of pulling his fingers out and forcing his body to take them back in. "So please… care of me."

"You're hurting yourself," John whispered from behind his hovering palm, his voice agonized as he watched Sherlock finger himself from the corners of his eyes. Sherlock could see the indecision on John's face, his blatant desire for Sherlock battling his ridiculous ideals of protection by by virtue of absence.

"Please," Sherlock begged, unashamed to throw away his pride to get what he wanted. "John. I want you."

John sighed then slowly, stiff-legged and clearly reluctant, stepped across the brief expanse of cave, stopping just out of reach of where Sherlock lay, staring down at him. His chest rose and fell rapidly as he panted from fear and arousal. Sherlock knew it was both: he could see the dilation of John's pupils, the pulse racing at the side of his neck, and the very prominent erection tenting the front of his worn pants. In the firelight, this close, John's eyes looked almost completely golden and Sherlock wondered if it was a trick of the light… or if John's beast was coming out to play.

John knelt by Sherlock, his brow furrowed and lips twisted in a grimace. Sherlock pulled his fingers free and rolled onto his back, trailing the damp digits over the skin of his hip to the cradle his splayed thighs created for his hand to rest. Before he could shove his fingers back into himself though, a hand tipped with fingernails slowly lengthening into claws gripped his wrist with an unfamiliar strength.

"I said, 'You're hurting yourself.'" John repeated, his voice a strange, quiet growl as it squeezed out from between clenched-together fangs. He stared down between Sherlock's legs, his face thrown into shadow making the illuminance of his eyes impossible by way of firelight.

"We can't...I can't do this…This is what I was afraid of…"

Sherlock cupped John's cheek, feeling the bristly whiskers beneath the delicate pads of his fingers and John stared at him, looking tortured and torn.

"You won't hurt me, John. I trust you." Sherlock rose up to kiss John, unfamiliar canines pressing against his lips through John's, creating an odd sensation. He opened his mouth, curious, snaking his tongue out and instantly becoming fascinated by the changing structure of tongue and teeth.

John's head, along with the rest of his body, seemed to slowly be growing larger. Right now the difference was minimal, but against Sherlock's tongue canines were growing larger and turning sharp, weapons in their own right, while the tongue against his was thinning and becoming oddly smooth.

Sherlock eased away from John's trembling form. The claws around his wrist tightened when he tried to retake his hand, but released him a second later. On his back, Sherlock stretched his arms above his head, rolling his body from his hips to his chest, a seductive stretch designed to entice and seduce. John's gold gaze darted to the swivel of Sherlock's cock for only a second before returning to eyes.

"Keep me warm, John," he whispered. "I need you."

"Oh, god," John breathed- then he abruptly lunged, clawed hands roughly turning Sherlock onto his stomach and hauling his hips up, pulling him onto his hands and knees. Sherlock's head spun with the sudden change in orientation and he barely had any warning before John spread his arse cheeks and licked - a bold, wet stripe - directly over his hole.

Sherlock gasped, jerking away in surprise, only for John to growl a wordless warning, dragging him back toward his face and impaling Sherlock on his tongue. The act was less of a surprise than the vigour it was performed with- John seemed to have a particular fondness for sticking his tongue in places Sherlock never quite expected. John had never been this… _vulgar_ about it, though. In fact, he was so involved that the sound of his slurping echoed back into the cave, doubling the sound, tossing it around and amplifying it until Sherlock felt like he was positively _dripping_ with saliva.

Transformation had lent an inappropriate length to John's tongue and it squirmed into Sherlock with an apparent, single-minded determination to touch his prostate. Sherlock craned his neck, tried to look back to see how far along in his transformation John was, but the increased pressure of claws against his tender skin and another warning growl at his squirming brought his eyes front and center again. Sherlock's curiosity burned, but it was quickly banked by his sudden and unignorable preoccupation with keeping himself upright when one of John's hands, rough with callouses, released his hip to curl around his cock and give it a light stroke. The coarse stimulation it hurt without any sort of lubrication and Sherlock opened his mouth to protest-

" _Sherlock_."

John's voice was unlike any Sherlock had ever heard. It was barely human. It made something long dormant, buried in Sherlock's mind, something evolution had almost ruled out, flare to life. His fight-or-flight sense took over and he struggled, to get free, suddenly very, very afraid.

A large hand- he almost dared to call it a 'paw', with a span that felt greater than that of Sherlock's face, pressed against the back of his neck. It bent him, with implacable strength, down to the cave floor, and stayed there, an unforgettable reminder that Sherlock was at John's mercy, that he was going nowhere.

It was almost arousing.

At the moment, though, it was more terrifying than arousing Sherlock thought, feeling the weight of that paw, the prick of claws, and the scrape of fangs over the tender flesh of his arse as a wet nose snuffled at his arsehole. The rising terror of being crushed, of being rent and torn and bitten made him reevaluate his initial argument to keep John in the cave and John's own frightened rebuttals.

He should have listened to John.

The muzzle pulled away from his arse, but the paw on his neck remained. Sherlock sucked in a slow, deep breath through his parted lips, trying to not inhale sand. Normally, he had no issue anticipating someone's next moves, especially someone he knew as well as he did his lover, but he had no idea what John was about to do. What was currently going through his feral mind.

Something large and furry pressed between Sherlock's legs, forcing them even further apart, and he stiffened as a tongue wrapped around his cock, wetting the sensitive, chafed skin. He bucked into the extreme heat without thinking, hips rolling to chase the pleasure. Something hard nudged the side of his cock and Sherlock froze, panic flooding him at the realization of what it was, at the danger of a fang so close to his erection. A whimper clogged his throat, filled his mouth, threatened to burst forth. His chest heaved as he struggled to regulate his breathing.

Another rumbling growl sounded, vibrating through Sherlock's body, and he went still. He was scared, more than he'd ever been, and he felt, as the body behind him shifted excitedly, that John- or rather John's beast- was pleased by his fear. He could probably smell it on Sherlock and he was responding to the scent like a predator nearing their trapped prey, knowing they were more powerful and their victory was assured.

As soft as his absolute terror should have made his erection, it was still physical stimulation and his body was responding accordingly. He'd already been warned not to move, but it was getting harder and harder to keep still when all he wanted to do was thrust into the soft tight heat wrapped around him. Suddenly, it pulled away and he whimpered at the loss of intense heat. John ignored him and dragged his tongue along the underside of his cock, then along his balls before he pulled fully away with a final swipe over his wet, open arsehole.

All the breath rushed from his lungs and the pressure of the paw at his neck increased as John leaned over him, the wet tip of his penis sliding against Sherlock's rim. On the cave wall, Sherlock watched the shadow of a half-man, obscenely bulky and head misshapen, rear over his body. The silhouette shifted and wavered as the creature shifted against him, trying to get his cock into the right angle to pierce and mount.

The size of it was a terror in itself. Sherlock was under no delusions that he was a 'size queen'- he had an entire trunk full of silicone back at Baker Street, many of which had been purchased for their large size and animalistic features. He'd spent many a night alone, fucking himself with them, biting his lip at the pleasurable burn as fantasies of being fucked by a nameless, faceless man spun out in his head in vivid detail.

But this... John was _massive_. The line of his cock was long and thick between his arse cheeks, so much bigger than even his largest toy. And the only preparation he'd had, while admittedly a very thorough rimming, was still just a rimming. His chest felt entirely too small as he struggled to pull air into his lungs. His hands curled and uncurled repeatedly and uselessly in the sand, granules becoming wedged under his nails as he scratched helplessly at the ground.

John roared and the paw pressed down harder. Sherlock squeezed his eyes shut, holding himself rigid for the beast pinning him at its mercy. His heart beat in his chest beat as if it would break his ribs and skip out into the snow as his brain ruthlessly calculated how much little pressure would be required before his neck snapped under John's paw. A sob ripped from his throat as he imagined what it would be like for John, coming out of his transformation in a few days to Sherlock's corpse spayed on their cave floor, leaking blood and semen from his arse.

He should have listened to John, he castigated himself. He shouldn't have been a brat. Should have listened...

It was that - guilt for pushing his lover, his love, into the position they were now in - that had Sherlock biting back another sob and trying to angle his hips up to help the creature behind him. Tears dripped down his face into the sand, creating tiny little clouds of dust against his cheek bones.

The first slide of John's cock into his arse _burned_. He felt big. Too big. Larger than Sherlock's brain could fathom and he opened his mouth, panting, as if that could somehow help him take such an intrusion. He knew there was slick- John's saliva had been copious, but it didn't feel like enough. He didn't know how he could take this.

There was no other choice.

The paw at his neck and the beast at his back gave him no other options. What Sherlock had wanted before, a fun but rough tumble during John's change, had turned into a brutal, fearful, painful reality. This wasn't the first time Sherlock's obstinance and headstrong personality had gotten him into trouble, and he hoped, as John increased the pressure on his neck, his penis sliding further inside, stretching Sherlock to accommodate him, that it wouldn't be the last.

"John…" he moaned weakly, the brush of John's pubic hair - or was it fur? - scratching against his arse as John bottomed out inside him. The beast behind him growled, the sound frightfully satisfied, and Sherlock almost lost himself to the way it rumbled like a vibrator down into the cock that was already stretching his limits.

He was full. So much more so than he'd ever been before. So much more than he ever knew he could be. Something heavy landed next to his head, the _fwump_ sending flurries of sand across his lips. Sherlock blinked furiously, trying to shake tear droplets and tiny clumps of sand from his eyes... and stared at what could only be described as a swollen, hairy hand next to his head.

John's fingers had doubled in size. The hair covering his arms had thickened and spread down across the backs of his hands and fingers, right up to the base of nails which had become wicked claws. The pressure on the back of his neck was lifted so suddenly that it left Sherlock gasping with the sudden ability to freely draw breath as the other paw landed on the other side of his head. He was effectively caged into place: John's powerful thighs restricted him from moving backwards, and his slowly distorting arms from moving forward or to the side. Before he could react, teeth closed over the curve of his neck and shoulder, the inherent danger of fangs pricking over his jugular more a deterrent to further movement than anything else.

Sherlock hissed when John suddenly withdrew, his larger-than-possible cock dragging against Sherlock's sensitive insides. He gasped as the pressure lessened, the burning stretch of John's invasion retreating and leaving him trembling with relief. Relief which was short-lived when John heaved forward, pushing against Sherlock as he awkwardly thrust into him again, his jaw still clamped on Sherlock's neck to keep him in place.

The angle _hurt_ , John's hips at the wrong height to enter him smoothly. Instead, he was hitting too low, too close in, jabbing in singular, hard thrusts that felt like they were going to punch through Sherlock's walls and leave him bleeding. He whimpered at the pain, but the second he tried to shift, a growl rumbled against his neck. A whine built in his throat and whistled out from between his gritted teeth, something high-pitched he'd never heard himself make before.

The thrusts paused, but the pain stayed, a low pulse centred where John had repeatedly pummeled. There was a soft, inquiring whine and Sherlock's mind froze at the sound, unable to comprehend where it had come from if it hadn't come from him. After a moment, when he realised John had imitated his whine of pain, he was unsure how to respond. Instinct made him whine back in response, and he braved shuffling his knees forward, trying to get the monstrous cock to pull free. There was another growl against his throat, but not an angry one, not one that made his heart stutter in fear.

John unclenched his jaws from Sherlock's neck, but before Sherlock could scramble away, that massive paw was back in place, pinning Sherlock to the ground. He cried out when John's cock slipped free of his arse- then jumped when a cold, wet nose jabbed itself against his tender hole.

He squirmed, as much as he was able, surprised by the unexpected sensation, and John growled again, the pressure of his paw against Sherlock's neck increasing until he almost couldn't breathe. The nose snuffled between his cheeks and then a broad swipe of tongue laved across his entrance. John's breath was hot and moist against his skin and Sherlock could feel the sheer amount of saliva running down his testicles, slicking his thighs as John licked him again and again. John didn't stop until Sherlock's legs were dripping wet from saliva from his pelvis to his knees.

The tongue pulled away and Sherlock held his breath, waiting for John to mount him again.. He jumped when John's paw curled around his hip and tugged. Cautiously, Sherlock pulled his knees up and together until he could angle his hips as high as they could go. After another pleased rumble, and it struck him suddenly that, normally, John was short enough that Sherlock had to spread his knees in order for his shorter lover to be able to reach where he needed. Now, John was growing into a bear, a creature larger and taller than Sherlock by far, and the point of entry was much higher.

John reared over him again, a chest much hairier - or furrier - than before pressing against Sherlock's back, the weight enough to press him back into the dirt. John's cock left a streak of wetness against his arse cheek as the creature behind him sought out his hole once more, the hips behind him thrusting with as much accuracy as they could. The cock poked his testicles next, making him jump, but John's third thrust landed between Sherlock's cheeks. The bear dragged his cock down until it caught on Sherlock's rim, and then pushed it back inside.

Sherlock could feel himself stretching around the vaguely familiar girth, and it wasn't until John's furred testciles bumped against his arse that Sherlock realised that, this time, there was no pain. John was deeper inside of him than he had been before, but the soreness of before was surprisingly and pleasantly absent. He could feel John's cock _throbbing_ inside him, a very strange sensation he'd never experienced before, but not an unpleasant one. It made him feel… full. Stuffed. Stretched to his limit. For the first time since John had penetrated him, Sherlock's still-hard cock throbbed hopefully, taking an interest.

He thought about reaching down and touching himself, but before he could, John shifted, cock sliding out, then humped forward, pushing himself back inside in a relentless grind. All the breath left Sherlock in a rush and pleasure fluttered through his pelvis.

There were no hesitant thrusts to start things again, just a sudden brutal thrust that rocked him forward. Then another and another in a flurry of quick succession before Sherlock could catch his breath. Each thrust sent a frisson of arousal through him, and his own cock, fully hard, slapped against his belly with every jolting motion. John was clearly too far gone, subsumed by his beast, because his thrusts were mindless, relentless, only seeking his own pleasure and making no shifts to find Sherlock's prostate like he usually did. It was frustratingly _not enough_. The brief friction on his cock was more of a tease and would never get him to orgasm, even with John's animalistic thrusts. Not unless he changed the angle.

Sherlock licked his lips and weighed his options, trying to decide if John would object to him trying to find his pleasure. He bit his lip and raised a very tentative and shaking hand, moving it slowly in search of John's head. He made contact, his fingers touching thick, shaggy hair, coarser than normal, and covering a head that was distinctly no longer _Homo sapiens_. The thrusts froze, and Sherlock froze in turn, terrified of angering the beast. Carefully, knowing he was pushing his luck, he stroked the fur, every motion cautious in the extreme, before he curled his fingers and gripped firmly, keeping John's head where it was. He whined in what he hoped was a way John understood and rolled his hips, encouraging his lover to begin thrusting again.

The bear did so immediately, surging forward with enough strength to shove the air from Sherlock's lungs. As the rhythm set in, Sherlock wriggled his hips, straining to find the perfect angle, not wanting to do too much and anger the beast, but desperate to find his own prostate. John's cock was so big it wouldn't take much to get Sherlock to his orgasm. He knew it wouldn't. Sweat broke out on his forehead as he arched his spine, pushing his hips up- just a bit more, it should be… almost…

He shouted when John's cock dragged directly across his prostate, the pleasure so intense that Sherlock's eyes screwed closed, his cock throbbing with renewed need as his fingers yanked at John's fur. There was a startled sound behind him and the head under his hand jolted forward, teeth clamping around his neck again even as John kept thrusting. The prick of sharp fangs did nothing to dampen the pulsations of pleasure as the violents jabs against prostate continued seamlessly. Now the size of John's cock was painfully arousing with the added stimulation, and he moaned, his fingers tightening in his lover's fur.

The paw next to his head shifted, dragging backwards and pressing against Sherlock's shoulder, immobilising him even further. The paw around his hip pulled away, working itself between the curve of his raised arm and mirroring the position of the other one. Sherlock was almost surprised to find that the limb in front of his eyes no longer resembled a hand in any way, but was an actual bear paw, a much more inelegant stump but edged with long claws and covered in thick, light brown fur. It was as the realisation registered that the body above him began to expand, growing larger and heavier, pushing his chest into the dirt. Even as it shortened his breath, his mind was more occupied by the swelling of the cock in him, lengthening, _thickening_.

It was a lot. It was so much. So so _so_. _much_.

"Fuck," he breathed, the word croaking out of his throat which felt parched.. The exaggerated length pressed against his prostate, hard and unyielding, almost brutish in its application. There was no finesse, no careful application to drive Sherlock to orgasm as John usually tried to do - there was only unrelenting pressure, forcing Sherlock to _take it_. There was no other option.

John thrust into him, now-hairy hips pressing against Sherlock's skin, the fur of his pelt tickling against the sensitive skin of Sherlock's thighs and arse distractingly. It reminded him, as if he needed reminding, that he wasn't being fucked by a human. That the bear at his back was in charge, he was being taken and fucked and consumed. Bred. And there was no escape. There was nothing he could do about it. The thought shouldn't have been arousing. Except, it was. So much so that Sherlock was dizzy with it.

John's furry mass shifted over him like waves of the ocean over the beach, each thrust coming faster and faster and jarring him so hard that his gritted teeth grated against one another. The increased pace alone made it clear that John was about to come, as if the tightening of fangs in his skin and the shortened breaths huffed against his sensitive neck wasn't enough of an indication. Which was good because Sherlock was about to come too. Fear had pumped excess amounts of adrenaline through his veins, mixed with the mild arousal from before John's change and the confusing but powerful arousal from after, and created a volatile cocktail that made him more sensitive than the time John had fingered him for a whole afternoon, bringing him to the brink over and over but whispering for him to wait… just wait...

In his precarious position, Sherlock couldn't reach and touch himself. His cock slapped wetly against his stomach and it was enough… it was almost enough...so close…

Sherlock clenched his eyes closed, moaning, angling his hips as much as he was able, guttural groans tearing from his throat as he tried to will himself to come. His fists were clenched so hard he could feel his fingernails biting into his palms. Every drag of John's cock was amplified, sending him into convulsions of near-ecstatic pleasure. Just something more… He needed it... Sherlock shuddered, panting, silently begging-

And then, abruptly, it was all enough.

Sherlock didn't recognize his own voice as he came,screaming, his body jerking as pulse after pulse of pleasure shocked his system, obliterating all thought in its wake. He was pure sensation, held together by flesh and bone, and for a split second, it didn't feel enough. It felt as if he were about to fly apart. Then the teeth in his skin pulled free and a roar split the air like thunder above his head.

The sound bounced off the rock walls and ceiling, reverberated, building off one another until everything seemed to vibrate, including Sherlock himself. It shook John's suddenly still cock inside of him, rubbing it over Sherlock's prostate until he was sobbing with the over-stimulation. He almost didn't feel the wet heat that was filling him until there was no more room it, until it gushed out of him, spilling down the back of his thighs in a thick, sticky stream.

He felt like jello when his lover's bellow finally faded: trembling, sobbing, slobbering. John's cock was still thick inside of him, the river of come surrounding it slowly dripping out onto the sand, inaudible under the burning huffs of breath stirring the curls that weren't slicked to his head with sweat. Sherlock's dazed mind half-expected to feel the cock in him shrink, for John's familiar hands to stroke through his hair and over his skin, comforting him as he was laid gently to the ground. Instead, the beast settled more firmly over him, crushing him beneath his weight and into the ground as a nose snuffled at his nape and a broad tongue, hot and rough like sandpaper, a polar opposite to the smoothness of John's tongue,, swiped over the back of his neck. Sherlock tensed and the tongue departed, the weight suddenly lifting. Cool air rushed over his heated, sweaty body, a glorious relief after the stifling heat of before.

A cold nose probed at his arse and, without warning, that rough tongue was swiping over his hole.

"Oh!" Sherlock jerked forward, trying to get away. The sensation of the coarse tongue on his stretched and sensitive rim was too much, intense in a confusing way. He couldn't parse it, couldn't tell if it were pain or pleasure. The bear growled, laving over his arse again, not put off when Sherlock squirmed, his hips jumping. If anything, Sherlock's shuddering movements seemed to excite John. He licked at the semen dribbling from Sherlock's arse, snuffling wetly between each swipe, and Sherlock could almost feel the satisfaction radiating from John as he smelled the evidence of himself on Sherlock.

He was trembling, legs and arms like jelly after his incredible orgasm, and Sherlock knew he only had another minute before he would collapse. Careful to broadcast his movements so John would know what he intended to do, Sherlock slowly eased himself onto his side in the bear didn't seem to mind, just followed along after, snuffling and licking contentedly. It kept Sherlock shaking, but the ground was an anchor, pressed all along his side from the tip of his outstretched arm to the smallest toe on his curled up leg. It seemed like hours passed under John's tongue, but at last, he gave one, slow lick and pulled away.

"John?" Sherlock called shakily, stretching out the arm he wasn't laying on for his partner. Instead of making contact with thick fur, his fingers only met air as John lumbered into view, stealing Sherlock's breath at the sight of the werebear for the first time.

John as a bear was _huge_. Much larger than a normal bear. His hulking body was covered in thick, soft-looking sandy colored fur, shaggy around his shoulders and belly. Sherlock wanted to plunge his fingers into the fur and feel how soft… but he was unsure of his welcome and kept his hands to himself. John's head, larger than four hands across, was covered in the same fur as the rest of his body. His blue eyes shone bright in the darkness of the cave as they stared at Sherlock from amidst the sea of sandy fur. His mouth was open and panting, humid breaths blowing into Sherlock's face, smelling of sex and semen, and his nose twitched slightly, but he didn't pull away. John's teeth loomed in Sherlock's face. Three inch long canines gleamed wetly, sharp and deadly. Sherlock shuddered, stomach flipping as he realized those teeth had moments ago been clamped around his neck. They could have crushed him, easily, without even trying.

The stupidity of what he'd goaded John into hit him hard and sudden. John had been right. He could have killed him, without even meaning to. Guilt nagged at Sherlock-

But John hadn't attacked him. John had done _well_. Had protected Sherlock even during the middle of their wild mating. So maybe, Sherlock thought, dismissing the guilt, he didn't have so much to be sorry for after all.

The bear settled down on his stomach in front of Sherlock, dropping his damp muzzle atop his paws. There was a spot, a few inches from the dark nose, dashed with a spot of semen that the long tongue hadn't reached. Sherlock stared at it, remembering the way the rest of that semen had been cleared from his own skin. He licked his lips and then leaned forward, laving his tongue over the spot of come.

John's fur tasted… cleaner than he'd expected. He'd had Redbeard's fur in his mouth as a child more times than he could count, but it had always tasted like dirt from all the outside playing they had done. His werebear's fur, however, tasted like John smelled: like John's hair and sweat and musk. And Sherlock's musk, especially all over his muzzle which, even after cleaning with his tongue, smelled more strongly of his semen than a flannel ever had after a rowdy round of intercourse with his lover.

There was a low rumble below his palm and with a bolt of fear, Sherlock realised that he'd placed it along the line of the bear's jaw for balance as he lost himself in his… 'grooming'. Heart pounding rapidly in his chest, Sherlock moved to pull away when John growled again and then butted the underside of the Sherlock's chin with his wet nose.

Sherlock laughed, a reedy sound of nerves and genuine happiness. "You like that?" he asked, unsure if John could understand him while he was in this form. John, however, roughly _cooed_ at Sherlock, a long, rolling yowl which Sherlock took to mean that "Yes, Sherlock, I enjoy when you use your tongue to groom me."

Sherlock dragged his tongue over John's muzzle and John huffed, eyes sliding closed in contentment. Bears couldn't purr, but Sherlock was convinced that if they could, John would be purring full-speed. Sherlock licked until his mouth was fuzzy and dry and he'd run out of saliva and John's fur was damp and slicked. When he realized Sherlock was done, John gently butted Sherlock in the chest, urging him to lay down, which Sherlock did with some trepidation. He wasn't ready to be mounted again and he was afraid that was what John had in mind.

Instead, John just rested his head on Sherlock's chest once Sherlock was prone, letting out a great sigh in happiness and went to sleep.

* * *

Sherlock woke with the world outside their cave dark and to the bear nudging him sleepily back onto his front and up onto his hands and knees. Confident that he wouldn't be hurt, but with the consequences of being mounted at the wrong angle fresh in his mind, Sherlock groggily hefted his arse in the air, but kept his shoulders flush to the floor, creating an awkward but no doubt enticing curve to his spine. One that his lover was not likely to be as appreciative of in this form as he was in his other.

The mating went much quicker this time, now that they were more familiar with one another. Sherlock was allowed to relieve himself before John mounted him again and again. For the rest of the day, Sherlock was barely given any time to rest. John didn't allow him very far - and definitely not out of his sight - and Sherlock was only allowed to stoke up the fire and gulp down some food before John was pushing at him again, grunting and nipping playfully at his skin.

* * *

Sherlock was exhausted. He could barely stay on his knees any longer, and they _hurt_. He'd been on them for almost three days straight, but he couldn't tell if they hurt more than his arsehole, which had been plundered and used by John's cock nearly every waking minute during John's transformation. When Sherlock's arse wasn't being ravaged by a horny bear, it was being licked clean by a hungry one, John's come cleaned up by his own tongue. Sherlock had never been more sore or more sensitive, and he doubted he'd had any respite when he'd passed out between rounds. He'd even had to eat while being mounted near the end, John's beast insatiable in its lust.

Sherlock was so fucked out, his hole so stretched and dripping wet from John's come, that it took a moment to realise the thrusts against his abused and swollen prostate were quickening past what the bear'd been capable of the last few days… and that the cock inside him was shrinking. In fact, it wasn't until fingers - actual fingers, not razor sharp claws - gripped his hips, a sweaty chest collapsed against his back, and a low groan of " _Sherlock_ " whispered against his neck that he really understood what had happened.

"John?" Sherlock's arms were shaking so badly that, when John's lessened weight collapsed against him, Sherlock couldn't hold himself up any longer. He fell, John's cock still lodged in his arse. Sherlock could barely feel it,, not after the days of being fucked by something much bigger. His own cock was only half-hard, swollen from coming so many times, but still forced to respond when the bear's cock pummeled his prostate. Sherlock huffed in great gulps of air as John's hips moved agitatedly against his arse, pushing himself into the loosened channel with an almost desperate agitation before John stiffened, groaning as he spent himself in Sherlock's body for the last time.

"I remember… you being afraid. You tried to get away from me and I couldn't stop," John slurred against his neck. "Please tell me you're okay. Sherlock. Please tell me I didn't hurt you." John's voice sounded choked, like he was trying not to cry, and Sherlock's heart skipped a beat. After everything that had happened, everything he had goaded John into, the last thing Sherlock wanted was for John to blame himself.

Sherlock opened his mouth to reply, but his throat was so parched that he had to swallow several times to wet his throat enough to push more than air through it.

"I panicked," he confessed, wishing he had the strength to thread his fingers through John's hair like he had comforted the werebear in the beginning. He didn't even try. He knew his arms didn't have the strength. "I thought I could handle it… and I could, after- But I didn't realise how different you would become with your change. I miscalculated."

"I scratched you," John murmured, his head rolling between Sherlock's shoulder blades. A soft tongue, softer and wetter than the bear's had been, stroked lines up Sherlock's shoulder where he remembered teeth closing over his skin. He shuddered, his skin too sensitive to pleasurably receive John's attention and he tensed, wanting to push John away but not wanting to hurt his feelings.

John stopped licking at Sherlock's skin on his own though and braced himself on his arms. "I'm going to… pull out," he warned, but nothing could have prepared Sherlock for the burning pain that swept through his lower half when John's cock finally slipped free of his arse. Everything was sore and rubbed raw, aching, and he couldn't stop the moan from tearing past his lips.

"I'm sorry, I'm so sorry," John whispered, gently spreading Sherlock's cheeks apart. Sherlock tensed, every movement too painful. "I'm sorry, Sherlock, but I have to see."

Sherlock didn't think he was torn. There would have been more pain, he thought, if he'd suffered an injury. But John was ominously silent behind him. "What is it?"

John was silent and Sherlock craned his neck to look. It hurt, moving, but the stoney look on his partner's face, seeing that expression, was well worth the pain. He could feel the volumes of ejaculate the bear had pushed into him leaking sluggishly from his hole, and he trembled and whimpered when two fingers pushed gently into him only to pull out a second later. They lifted into his view and he blinked in surprise at the sight of normally white come tinted pink.

"Am I bleeding?" he asked, feeling a bit shocked. He knew it had been a bit rough in the beginning, a bit dry because they had used nothing for lubrication besides John's saliva, but he'd been so soaked in semen the last few days; He'd never been wetter.

"I'd have to clean you out and look to be sure, but I believe it's only minor tearing. Consistent with improper amounts of lubrication." John went silent and dropped his gaze, wiping his wet fingers off on his own hip. His gaze seemed to be riveted to Sherlock's arsehole, face expressionless.

"John?" Sherlock asked softly, unsure what else to say.

"It could have been worse," John said, as if reassuring himself. "I remember you trying to get away, that first time. I trapped you and mounted you, forced myself inside of you, and you had to let me take you for fear of repercussion. I could have killed you, Sherlock."

"I wanted it-"

"Don't," John snapped. "Don't, Sherlock. Just… That doesn't make it right. You didn't know what to expect, before… but I knew." He trailed his fingers over Sherlock's puffy hole, looking so unhappy Sherlock wanted to hug him but couldn't make his limbs work properly. "I knew what it would be like. I should have stopped myself. I should have… should have left before it got out of hand." He sighed. "But I wanted it too. I wanted to know what it would be like… to have you while I was… like that. And you kept- but that's no excuse. Never again, though," he said sternly, pulling himself away from Sherlock and steeling his expression. "Never again. This is never happening again."

Sherlock watched as John stood and moved around the cave, locating his matches and starting a fire, which had died during the last stages of the rut. He stayed, crouched naked by the fire, even after it was roaring again, eyes open but unseeing, for so long that Sherlock started to get worried.

"John, come here."

Blue eyes slid to him, but then went back to the fire and John didn't move.

"John," he said again, firmer. "Come. Here."

John stared into the fire a little longer, and then stood with a deep sigh, moving over and sitting down next to Sherlock's head.

Sherlock sighed and dragged his arm across the sand, curling weak fingers around John's wrist and tugging. John sighed again, so deep it seemed to come from his very soul, and laid down next to him, hesitantly scooting close enough to wrap an arm around Sherlock's waist.

"Don't blame yourself for this, John," Sherlock demanded, voice so imperious that John's lips twitched into an almost-smile." You warned me. You told me this was unwise, and I provoked you. I _wanted_ this. Yes, the first time… terrified me, but after that, after I fully understood what it was going to be like spending this time with you, I enjoyed our later couplings. Though I must admit, I was surprised by how… amorous you were in your other form."

"I… all of that doesn't… never again, Sherlock," John whispered fervently. "Never again." He pressed a reverent kiss to Sherlock's temple, trembling. "Even if you enjoyed it, there were so many times when it could have gone wrong. I could have lost control. Someone could have found us-"

"Unlikely," Sherlock snorted.

"It was dangerous," John stressed. "And not worth it. You're important to me, you complete idiot. I don't want to do anything to ever hurt you. Even if it's something you want. Even if it's me. _Especially_ if it's me."

Sherlock snuggled next to John, exhausted, and decided to let it go for now. There would be plenty of time to convince John it had all been fine. For now, he had other things on his mind: like, sleeping. Letting his body recover. And marshaling a good enough argument to convince John to leave his cave and come back to London with him.

* * *

 **Tbh, we wrote this months ago, but didn't end up finishing editing until today because we're terrible, wonderful ladies with hectic lives. Please let us know how we did, and come check out our tumblrs: starrysummer-nights and themadkatter13fanfiction (reblog the** **post/137716639423)!**


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